1. Field of the Invention
The present invention relates generally to power conversion, and more particularly to inverters for converting direct current power into alternating current power.
2. Description of Related Art
Aircraft power systems commonly include power converters to convert power of one type to a type suitable for power-consuming devices coupled to the aircraft power distribution system. For example, rectifiers are generally employed to convert alternating current (AC) power into direct current (DC) power. Inverters are typically employed to convert DC power into AC power. One type of inverter commonly employed is such applications is the neutral-point-clamped (NPC) inverter. Neutral-point-clamped inverters are generally coupled to a DC power source with a DC link having a source lead and a return lead. An additional midpoint lead is created by the series connection of capacitors to the power source. The voltage differential between the source and returns leads and midpoint lead is generally about half the potential difference across the power source, thereby reducing the voltage rating of components required for the inverter.
Some multilevel inverters can exhibit voltage imbalance across DC link leads. DC link capacitors are commonly employed to reduce voltage imbalance, generally with a first capacitor connected between the DC source lead and the midpoint lead and a second capacitor disposed between the DC return lead and the midpoint lead. The DC link capacitors are typically sized according to the voltage imbalance characteristic of a specific application.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved power converters. The present disclosure provides a solution for this need.